CN104634645A - Black cotton soil California bearing ratio test method - Google Patents
Black cotton soil California bearing ratio test method Download PDFInfo
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- CN104634645A CN104634645A CN201410796145.7A CN201410796145A CN104634645A CN 104634645 A CN104634645 A CN 104634645A CN 201410796145 A CN201410796145 A CN 201410796145A CN 104634645 A CN104634645 A CN 104634645A
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- bearing ratio
- california bearing
- test
- cylinder
- california
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- 239000002689 soil Substances 0.000 title claims abstract description 53
- 229920000742 Cotton Polymers 0.000 title claims abstract description 28
- 238000010998 test method Methods 0.000 title claims abstract description 17
- 238000012360 testing method Methods 0.000 claims abstract description 60
- 230000035515 penetration Effects 0.000 claims abstract description 31
- 238000012937 correction Methods 0.000 claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 9
- 238000012935 Averaging Methods 0.000 claims abstract description 4
- 239000002245 particle Substances 0.000 claims abstract description 4
- 239000010421 standard material Substances 0.000 claims abstract description 4
- 238000002347 injection Methods 0.000 claims description 17
- 239000007924 injection Substances 0.000 claims description 17
- 238000013138 pruning Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 17
- 239000000463 material Substances 0.000 abstract description 4
- 238000007790 scraping Methods 0.000 abstract 1
- 238000011068 loading method Methods 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 239000004927 clay Substances 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000002715 modification method Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 229910052900 illite Inorganic materials 0.000 description 1
- 238000005213 imbibition Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052901 montmorillonite Inorganic materials 0.000 description 1
- VGIBGUSAECPPNB-UHFFFAOYSA-L nonaaluminum;magnesium;tripotassium;1,3-dioxido-2,4,5-trioxa-1,3-disilabicyclo[1.1.1]pentane;iron(2+);oxygen(2-);fluoride;hydroxide Chemical compound [OH-].[O-2].[O-2].[O-2].[O-2].[O-2].[F-].[Mg+2].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[K+].[K+].[K+].[Fe+2].O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2.O1[Si]2([O-])O[Si]1([O-])O2 VGIBGUSAECPPNB-UHFFFAOYSA-L 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004162 soil erosion Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention provides a black cotton soil California bearing ratio test method. The method comprises the following steps: step 1, assembling a California bearing ratio test tube, wherein the California bearing ratio test tube is formed by vertically splicing three parts of test tubes, and the test tubes are fixed by bolts in pairs; step 2, feeding test samples into the test tube for three times (depending on the maximum particle size) to perform a penetration test; step 3, removing the uppermost test tube, chipping off a soil sample at the upper part to perform a penetration test, then removing the second layer of the test tube, scraping the soil sample, and then performing a penetration test again; step 4, performing a California bearing ratio value correction test on different California bearing ratio test tube height standard materials to acquire a correction coefficient; and step 5, correcting values obtained by multiplying California bearing ratio values of the middle and low layer of the soil sample and the lower-layer soil sample by the correction coefficient into standard California bearing ratio values, and then averaging with the California bearing ratio value of a standard test to obtain final California bearing ratio values of the test samples. According to a California bearing ratio obtained by using the method disclosed by the invention, a real California bearing ratio value of a black cotton soil material can be reflected more accurately, and the changes of internal water content of the test samples after water saturation can be shown.
Description
Technical field
The present invention relates to the test method of a kind of highway engineering black cotton regur soil California bearing ratio (California Bearing Ratio).
Background technology
Bearing-ratio test is first proposed by California, USA Highway Administration Bureau, is called for short California bearing ratio (California Bearing Ratio) test.So-called California bearing ratio value, when referring to that test portion injection amount is 2.5mm, the ratio of standard load intensity when unit pressure is pressed into identical injection amount to standard rubble.California bearing ratio value worldwide extensively adopts as the intensity index of roadbed and ground surface material, abroad one of major parameter doing Flexible Pavement Design.In the Flexible Pavement Design of China, though using the modulus of resilience of subgrade soils and ground surface material as design parameter, in subgrade and pavement job specifications will California bearing ratio as a mechanical index.Regulation in China " highway subgrade design specifications " (JTJ013-2004), embankment fill material is selected primary according to being California bearing ratio intensity index, in table 1.
The minimum bearing ratio requirement of table 1 roadbed filler
Black cotton regur soil is a kind of special cohesive soil, is a kind of many cracks of being formed in nature geological process and has the geologic body of remarkable swell-shrink characteristic, and clay component forms primarily of the mineral montmorillonite of strong hydrophilicity and illite.Black cotton regur soil has overconsolidation, fissurity, water-swellable, dehydration shrinkage ftractures and sex change equals the different engineering properties of normally consolidated clay repeatedly.By the California bearing ratio test method of existing standard, the standard California bearing ratio value of black cotton regur soil seldom can reach the requirement (California bearing ratio > 3%) of the minimum California bearing ratio value of roadbed filling.Therefore the black cotton regur soil Chang Zuowei side of abandoning discards, and not only causes waste and soil erosion, and affects surrounding enviroment.
Reinvent black cotton regur soil and there is extremely low infiltration coefficient, California bearing ratio black cotton regur soil sample satisfy water 4 round the clock after, its interior moisture content distributed pole is uneven, presents top water cut high, the trend reduced gradually downwards, after arriving certain depth, sample water content distribution becomes more stable situation.Black cotton regur soil has the characteristic of water suction black cotton regur soil, after meeting water, intensity significantly reduces, full water 4 round the clock after, veneer of soil expands completely, loose one-tenth stream moulds shape, have no intensity can say, and the depth of penetration that standard California bearing ratio test specifies is only 2.5mm (5mm), well imagines, this value is representative poor as the intensity index of black cotton regur soil.Therefore, be necessary that proposition is a kind of reasonably to improve one's methods for the California bearing ratio test of black cotton regur soil.
Summary of the invention
Technical matters: the present invention be directed to the disappearance that above-mentioned prior art field exists, provide a kind of California bearing ratio test method of applicable black cotton regur soil, to solve the intensity evaluation problem of black cotton regur soil.
Technical scheme: the invention provides following technical scheme:
A kind of black cotton regur soil California bearing ratio (California bearing ratio) test method, the method comprises the steps:
Step 1: assembling California bearing ratio examination cylinder: California bearing ratio examination cylinder tries cylinder by three parts and is vertically assemblied to form, and uses bolt to fix between any two;
Step 2: divided by sample three loadings examination cylinder (depending on maximum particle diameter) to carry out penetration test;
Step 3: remove and try cylinder topmost, top soil sample of pruning carries out penetration test, then removes second layer examination cylinder, again carries out penetration test after scabbling soil sample;
Step 4: the California bearing ratio value correction test carrying out different California bearing ratio examination cylinder Height Standard material, obtains correction factor;
Step 5: the California bearing ratio value of middle lower floor and lower floor's soil sample is multiplied by after correction factor is modified to standard California bearing ratio value, is averaging the final California bearing ratio value as sample with the California bearing ratio value of code test.
Preferably, the size of 3 examination cylinders of California bearing ratio examination cylinder is respectively: above interview cylinder internal diameter 152mm, high 40mm, middle examination cylinder internal diameter 152mm, high 40mm, lower interview cylinder internal diameter 152mm, high 90mm.
Preferably, every two of said California bearing ratio examination cylinder are tried to be connected by 2 bolts between cylinders.
Preferably, step 4 comprises, and in obtaining step 2, the unit pressure value of different depth of penetration, is designated as P1; Obtaining step 3 kinds is then removed and is topmost tried cylinder, uses straight scraper to prune upper sample, carries out penetration test, obtain the unit pressure value of different depth of penetration, be designated as P2 after leveling; Then remove second layer examination cylinder, again carry out penetration test after scabbling sample, obtain the unit pressure value of different depth of penetration, be designated as P3;
The correction factor of the 2nd layer of injection is δ 2=P1/P2, and the correction factor of the 3rd layer of injection is δ 3=P1/P3.
Beneficial effect: this test method solve black cotton regur soil satisfy water 4 round the clock after the problem of interior moisture content skewness and veneer of soil cause intensity extremely attenuation problem due to imbibition.And propose the modification method that differing heights California bearing ratio examination cylinder carries out California bearing ratio test California bearing ratio value.The examination improvement of cylinder and the proposition of modification method can obtain the California bearing ratio value of black cotton regur soil more accurately, are conducive to making accurate evaluation to the intensity of black cotton regur soil.
Accompanying drawing explanation
Below with reference to accompanying drawing, a kind of black cotton regur soil California bearing ratio test method of the present invention is described in detail.
Fig. 1 is a kind of black cotton regur soil California bearing ratio test method examination cylinder pie graph;
Fig. 2 is examination cylinder bolt position flat distribution map.
In figure, 1. top examination cylinders, try cylinder 2., 3. bottom examination cylinder, 4. steel disc, 5. set bolt, 6. bolt hole.
Embodiment
Black cotton regur soil California bearing ratio (California bearing ratio) test method provided by the invention, the method comprises the steps:
Step 1: assembling California bearing ratio examination cylinder: California bearing ratio examination cylinder tries cylinder by three parts and is vertically assemblied to form, and uses bolt to fix between any two;
Step 2: divided by sample three loadings examination cylinder (depending on maximum particle diameter) to carry out penetration test;
Step 3: remove and try cylinder topmost, top soil sample of pruning carries out penetration test, then removes second layer examination cylinder, again carries out penetration test after scabbling soil sample;
Step 4: the California bearing ratio value correction test carrying out different California bearing ratio examination cylinder Height Standard material, obtains correction factor;
Step 5: the California bearing ratio value of middle lower floor and lower floor's soil sample is multiplied by after correction factor is modified to standard California bearing ratio value, is averaging the final California bearing ratio value as sample with the California bearing ratio value of code test.
The size of 3 examination cylinders of California bearing ratio examination cylinder is respectively: above interview cylinder internal diameter 152mm, high 40mm, middle examination cylinder internal diameter 152mm, high 40mm, lower interview cylinder internal diameter 152mm, high 90mm.
Connected by 2 bolts between every two examination cylinders of said California bearing ratio examination cylinder.
Step 4 comprises, and in obtaining step 2, the unit pressure value of different depth of penetration, is designated as P1; Obtaining step 3 kinds is then removed and is topmost tried cylinder, uses straight scraper to prune upper sample, carries out penetration test, obtain the unit pressure value of different depth of penetration, be designated as P2 after leveling; Then remove second layer examination cylinder, again carry out penetration test after scabbling sample, obtain the unit pressure value of different depth of penetration, be designated as P3;
The correction factor of the 2nd layer of injection is δ 2=P1/P2, and the correction factor of the 3rd layer of injection is δ 3=P1/P3.
Test operation step:
(1) maximum dry density and the optimum moisture content of soil sample is tried to achieve by wet method modified compaction test.
(2) get the raw materials ready, by soil sample air-dry (if desired can in drying in oven, stability contorting is at 50 DEG C), smash to pieces with wooden mallet and cross 5mm sieve.
(3) shelving, prepares 3 test specimens by optimum moisture content.Should note during operation water consumption, mix even, airtight after infiltrating time (24h) and each test specimen of Accurate Determining infiltrate after water cut.
(4) hit the preliminary work in fact, examination cylinder is fixed on base plate after weighing, and cushion block is put into cylinder, and on cushion block, puts a filter paper, set up the collar.
(5) hit reality, adopt standard heavy duty to hit solid yardage method.
(6) unload lower collar, hit real test specimen with straight scraper along examination cylinder top equating, surface irregularity place fines is repaired.Take out cushion block, claim examination cylinder and test specimen quality.
(7) a circular filter paper is placed in the surface of test piece fixed, and adds porous plate and 4 pieces of Loading Plates thereon, bottom adds Porous Base, and examination cylinder is put into tank, and in tank, the water surface is higher than the above 25mm of test specimen end face.Test specimen satisfies water 4 round the clock.
(8) take out test specimen, pour out the water of test specimen end face, leave standstill 15min, allow its draining, shed Loading Plate, porous plate, base plate and filter paper, weigh, and calculate humidity change and variable density.
(9) be put on lifting table by test specimen, injection bar applies 45N load, adjustment dynamometry and survey distortion dial gauge reading are integer, and write down initial reading.
(10) loading makes injection bar with the speed Specimen of 1 ~ 1.25mm/min, injection amount when dial gauge is some integer reading (as 20,40,60) in record dynamometer, and notes making injection amount be 250 × 10
-2during mm, can have the reading of more than 5, therefore, first reading in dynamometer should be injection amount is 30 × 10
-2about mm.
(11) remove top examination cylinder, with straight scraper along examination cylinder limit equating test specimen, surface irregularity place fines is repaired.First time penetration test, carries out injection by standard California bearing ratio test method.Unit pressure when record injection amount is 2.5mm.
And in the middle part of the ground floor soil sample of pruning, get 50g soil sample put into baking oven, calculate its water cut after drying.
(12) remove middle part examination cylinder, with straight scraper along examination cylinder limit equating test specimen, surface irregularity place fines is repaired.Second time penetration test, carries out injection by standard California bearing ratio test method.Unit pressure when record injection amount is 2.5mm.And in the middle part of the second layer soil sample of pruning, get 50g soil sample put into baking oven, calculate its water cut after drying.
(13) after penetration test terminates, in the middle part of lower floor's soil sample, get 50g soil sample put into baking oven, after drying, calculate its water cut.
Claims (4)
1. a test method for black cotton regur soil California bearing ratio, is characterized in that, the method comprises the steps:
Step 1: assembling California bearing ratio examination cylinder: California bearing ratio examination cylinder tries cylinder by three parts and is vertically assemblied to form, and uses bolt to fix between any two;
Step 2: sample is divided and loads examination cylinder for three times, depending on maximum particle diameter, carry out penetration test;
Step 3: remove and try cylinder topmost, top soil sample of pruning carries out penetration test, then removes second layer examination cylinder, again carries out penetration test after scabbling soil sample;
Step 4: the California bearing ratio value correction test carrying out different California bearing ratio examination cylinder Height Standard material, obtains correction factor;
Step 5: the California bearing ratio value of middle lower floor and lower floor's soil sample is multiplied by after correction factor is modified to standard California bearing ratio value, is averaging the final California bearing ratio value as sample with the California bearing ratio value of code test.
2. black cotton regur soil California bearing ratio test method according to claim 1, it is characterized in that, the size of 3 examination cylinders of California bearing ratio examination cylinder is respectively: above interview cylinder internal diameter 152mm, high 40mm, middle examination cylinder internal diameter 152mm, high 40mm, lower interview cylinder internal diameter 152mm, high 90mm.
3. black cotton regur soil California bearing ratio test method according to claim 1, is characterized in that, is connected between every two examination cylinders of said California bearing ratio examination cylinder by 2 bolts.
4. black cotton regur soil California bearing ratio test method according to claim 1, it is characterized in that, step 4 comprises, and in obtaining step 2, the unit pressure value of different depth of penetration, is designated as P1; Obtaining step 3 kinds is then removed and is topmost tried cylinder, uses straight scraper to prune upper sample, carries out penetration test, obtain the unit pressure value of different depth of penetration, be designated as P2 after leveling; Then remove second layer examination cylinder, again carry out penetration test after scabbling sample, obtain the unit pressure value of different depth of penetration, be designated as P3;
The correction factor of the 2nd layer of injection is δ 2=P1/P2, and the correction factor of the 3rd layer of injection is δ 3=P1/P3.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410796145.7A CN104634645B (en) | 2014-12-18 | 2014-12-18 | A kind of black cotton regur soil California bearing ratio test method |
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| CN201410796145.7A CN104634645B (en) | 2014-12-18 | 2014-12-18 | A kind of black cotton regur soil California bearing ratio test method |
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| CN104634645A true CN104634645A (en) | 2015-05-20 |
| CN104634645B CN104634645B (en) | 2017-06-16 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109211632A (en) * | 2018-09-17 | 2019-01-15 | 江门市建联检测有限公司 | A kind of forming method of the carrying of soil than testing test block |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE829984A (en) * | 1975-06-06 | 1975-10-01 | THRESHING PROBE | |
| CN201000450Y (en) * | 2006-10-09 | 2008-01-02 | 长沙理工大学 | California bearing ratio experiment barrel |
| CN101556271A (en) * | 2009-04-17 | 2009-10-14 | 江苏省交通科学研究院股份有限公司 | Method for detecting compacting quality of roadbed |
| CN103267807A (en) * | 2013-05-03 | 2013-08-28 | 上海和伍新材料科技有限公司 | Method and device for calibrating probe in ultrasonic detection equipment |
| CN103323322A (en) * | 2013-05-20 | 2013-09-25 | 东南大学 | Graded gravel California bearing ratio value determination method |
| CN203705235U (en) * | 2014-01-01 | 2014-07-09 | 浙江省建设工程质量检验站有限公司 | Static shear sample part instrument |
-
2014
- 2014-12-18 CN CN201410796145.7A patent/CN104634645B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE829984A (en) * | 1975-06-06 | 1975-10-01 | THRESHING PROBE | |
| CN201000450Y (en) * | 2006-10-09 | 2008-01-02 | 长沙理工大学 | California bearing ratio experiment barrel |
| CN101556271A (en) * | 2009-04-17 | 2009-10-14 | 江苏省交通科学研究院股份有限公司 | Method for detecting compacting quality of roadbed |
| CN103267807A (en) * | 2013-05-03 | 2013-08-28 | 上海和伍新材料科技有限公司 | Method and device for calibrating probe in ultrasonic detection equipment |
| CN103323322A (en) * | 2013-05-20 | 2013-09-25 | 东南大学 | Graded gravel California bearing ratio value determination method |
| CN203705235U (en) * | 2014-01-01 | 2014-07-09 | 浙江省建设工程质量检验站有限公司 | Static shear sample part instrument |
Non-Patent Citations (1)
| Title |
|---|
| 孙波等: "膨胀土用作路堤填料的工程适应性研究", 《民营科技》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109211632A (en) * | 2018-09-17 | 2019-01-15 | 江门市建联检测有限公司 | A kind of forming method of the carrying of soil than testing test block |
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Granted publication date: 20170616 |